https://musicbrainz.org/edit/46432175 can't apply, I assume because it tries to merge the tracks by position, and the positions are staggered and of different ranges. The recording merges also look messed up for the same reason, although that's just for display.

I propose to not allow entering merges like this, because it would be a pain to make the merges not align by track.position exactly, and might cause other issues if we don't. Unfortunately, it's currently impossible to convert track 1 on a non-pregap release into a pregap track without losing all the track IDs, so that needs to be fixed as well, otherwise the releases can't be made mergeable.